具有温度补偿的光纤位移传感器

位移测量是结构健康检测的重要参量之一.本文提出了一种双悬臂梁粘贴光纤光栅的位移传感器,它将位移变化转换成两只光纤光栅的波长移动,实现对位移量的绝对测量.通过引入对称补偿光纤光栅的方法解决了温度与位移交叉敏感的问题.推导了位移传感器的工作原理,完成了相关实验,并分析了传感器所产生误差的来源.实验结果表明,在量程为20 mm的时候,位移灵敏度为123 pm/mm,温度补偿前,温度对位移的影响是234.9 μm/℃;温度补偿后,温度对位移的影响为17 μm/℃.本位移传感器量程大、线性好、准确度高,不易受恶劣环境影响.

A Fiber Optic Displacement Sensor with Temperature Compensation

Displacement measurement is one of the most important parameters to be monitored. A Fiber Bragg Grating (FBG) displacement sensor based on double cantilever beams is developed, in which the displacement is changed to wavelength shifts of two FBGs. The influence resulted from temperature to displacement measurement is reduced by the differential of the two wavelengths, since they have the same wavelength shifts when they are in the same environment. The operation principle based on FBG theory is deduced, and the reasons of measurement error are analyzed. Experimental results show that the displacement sensitivity is 123 pm/mm in the range of 0~20 mm, and the temperature cross-sensitivity is 17 μm/℃ after temperature compensation. With the particular advantage, this FBG displacement sensor may find tremendous applications in engineering.